1. Field of the Invention
The present invention relates generally to the art of cutting food products and more specifically to a device for cutting vegetables, such as potatoes, into desired shapes. Still more specifically, the present invention in its most preferred form relates to a system for cutting helical strips of potatoes and includes a water system for aligning and feeding potatoes through a cutting mechanism.
2. Description of the Prior Art
Many devices of differing designs have been described in the prior art for cutting various vegetable materials, including potatoes. Many of the devices described in the patent literature relate to devices for use at home or for the handling of individual food products. Simple examples of such systems would be found in most households, i.e. rotary food processors, vegetable slicers, etc.
The commercial cutting of potatoes into variously shaped pieces has also been known for a number of years. Frozen potatoes can be purchased in any grocery store in a variety of shapes, including the common shoestring shape (generally square in cross-section and having a length of 3-4 inches or longer), crinkle-cut potatoes which have a corrugated appearance, and in recent years, helical strips of potatoes which are of the type sold by the assignee of the present invention under the trademark CURLEY Q.RTM..
The evolution of the helical potato is a phenomenon of the late 80's Somewhat similarly shaped products originated prior to that time from hand crank machines used at county fairs and in small restaurants. These early machines for making helical strips typically had a system for impaling the potato on a rotating, screw driven holder and rotating it into a fixed knife to produce helical strips. The product was typically uneven in consistency and the process was always slow. Moreover, the process typically resulted in inefficient use of the potato product, as the butt ends of the potato were not included in the final product and were discarded or used for other purposes.
It was not until the assignee of the present invention introduced the CURLEY Q.RTM. potatoes in 1983 that the cut variety became popular on a national basis. The reason for the increase in popularity was the improved product quality and the ability to commercially manufacture the product using the cutting device described in U.S. Pat. No. 4,644,838, issued Feb. 24, 1987 to Samson et al. and entitled "Apparatus for Helical Cutting of Potatoes". In this device, various conveyor systems are described for bringing product to a plurality of tubes. A potato is deposited in each tube and held therein against rotation by a plurality of spring-loaded, generally triangularly shaped fingers. A knife blade which includes a number of upstanding scoring blades and a radially extending cutting blade is located beneath the tube and is designed to be rotated during the cutting operation. The patent further describes a plunger system for exerting downwardly extending forces on the potato held in the tube to push the potato through the cutting knife, resulting in a plurality of helical strips of varying diameters, depending on the distance from the axis of the tube.
In the preferred embodiment of the Samson et al. patent, the bottom of the plunger includes recesses to receive the upstanding scoring knives so that the entire potato can be cut using the process, thereby avoiding prior difficulties and the waste resulting from butt ends. The knife itself is rotated by a motor and a belt, and a stationary tube receives the product. After being cut, separation of the various coils for improved product appearance takes place. Initially such separation was accomplished by hand. Later, mechanical coil separators were used for this part of the process.
Since the introduction of this product by the assignee of the present invention, numerous other frozen potato manufacturers have introduced similarly shaped products, some using different cutting technologies. Moreover, the assignee of the present invention has itself developed improvements, such as a "Cutting Assembly" described in U.S. patent application Ser. No. 07/682,653, filed Apr. 9, 1991, in the name of Foster. In this application, a tiered blade is used instead of the blade described in the Samson et al. patent. The blade is positioned to form concentric longitudinal cuts in the potato such that helical strips are produced in an efficient and reproducible manner.
Other patents have issued to competitors of the assignee on cutting knives and on production devices, such as the systems described in U.S. Pat. No. 4,926,726, issued May 22, 1990 to Julian and entitled "Food Processing Apparatus" and U.S. Pat. No. 4,979,418, issued Dec. 25, 1990 to Covert et al. and entitled "Food Processing Apparatus". In both patents, a rotating cutter head is used to produce helical strips from potato product forced through the knife using an elongate feed system including conveyors and spring biased paddle and spike members. The feed device is described as being very similar to the SC-120 Corn Cutter marketed by FMC Corporation to feed cob corn to a cutting assembly, which machine is described in detail in U.S. Pat. No. 2,787,273. The feed conveyor includes U-shaped areas for centering the potato, dogs to maintain product alignment and a spring loaded top plate floating on the top of the potatoes as they pass along the line. As the potatoes enter the area adjacent the rotating cutting head, they pass through a series of pairs of shafts extending across the path of travel, the first two shaft pairs including a plurality of paddles which urge the potatoes forwardly toward the knife, and the last pair of shafts including a plurality of spikes which grasp and penetrate the potato as it is being pushed through the cutting head. Each pair of shafts, one above and one below the feed path, is spring biased to compensate for different sized potatoes. The device can operate continuously with one potato following another through the system.
Water gun systems have also been known for some time in the potato processing field, i.e. systems which use a tube to align potatoes and water pressure to push the potatoes through the tube at increasing velocity and through knives of various types. Typically, such devices have been used for making straight cut potatoes, wherein fixed, crossed blades were mounted at the outlet of the water gun and the potatoes were merely forced therethrough at high speed.
One attempted use of a water-feed system for the preparation of helical cut french fries is described in European Patent Application No. 0 377 451, published Jul. 11, 1990 and filed by Lamb-Weston, Inc. An embodiment disclosed in this application shows a tubular, elastic tapered feed tube for feeding potatoes under the force of water pressure through a rotating cutting head to form helical potato strips. According to the application, the elastomeric member expands once the potato reaches the tapered end, thus decreasing the velocity of the potato, but increasing the water pressure to the range of 15-25 pounds per square inch. The applicant indicates that the potato is forced evenly and gently onto a central alignment tube and that the alignment tube also serves to decelerate the potato before the slicing blades cut the potato into helical strips. The specification also indicates that no external mechanical devices touch the potato, thus eliminating any damage to the outside of the potato.
It would represent a significant advance in this art to provide a water feed system in which potatoes could be forced through a cutting head to form cut product at a consistent velocity and on a continuous basis, without the need to raise and lower a plunger between each product cutting step. Therefore, a system which would produce a high quality product at increased speeds, and using less energy in the operation of the equipment, would represent a very substantial advance in the art.